Recently, according to the development of the recording medium, a recording medium having record density of above tens Mbps has appeared. But a conventional reproducing apparatus using a magnetic head does not function very well for a high frequency signal, for instance, above 10 MHz. In particular, according to the development of the digital techniques, such as the digital audio tape, a digital VTR, etc., the required recording density of data is highly increased, but the recording density, for instance, above 20 Mbps can not be achieved because of the limitation of the above-described reproducing apparatus. Moreover, under such high recording density, when the recorded data is an NRZ (non-return-to-zero) type isolated pulse, it is not possible for the reproducing apparatus to exactly reproduce the record data, so that the deterioration of the reproduced sound quality or the reproduced picture quality is caused.
Conventionally, for instance, a reproducing equalizer such as U.S. Pat. No. 4,714,958 shown in FIG. 1 is used to improve the quality of a reproduced signal. The reproducing equalizer, which is composed of a video processor, divides a composite video signal received in an input terminal 1. The divided signals are respectively amplified in amplifiers 2 and 3, and one of amplified signals is delayed by a predetermined time in a phase shifter 4 to be mixed with the other signal in a mixer 5, thereby improving reproduced picture quality.
Though the above described reproducing equalizer is efficient in a standard NTSC type TV or a reproducing apparatus, when the reproducing equalizer is used for a recording medium having high recording density of tens Mbps as described above, there arise problems such that the complete equalization of the reproduced waveform is impossible and the reproduced picture quality or the sound quality is deteriorated.